1. Field of the Invention
The present invention relates to surgical devices employed for minimally invasive surgery. More specifically the invention relates to a sensor mounting device and system which provides secured non-damaging electronically communicative engagement of a medical sensor to a lead wire and surgical instrument. The invention is most suitably adapted for engagement with needles, guide wires, catheters, cytology brushes, biopsy forceps, and other devices employed using electronic navigation to determine positioning in the body of a patient.
2. Prior Art
The medical industry is a field which is constantly seeing technological changes, advancements, and improvements. Minimally invasive surgery and computer assisted surgery (CAS) is a recent development which allows physicians to perform procedures with the aid of computer technology which provides a means to visually determine instrument positioning in the body of a patient. Such CAS systems are a promising factor in the development of new robotic surgery and improvement of old minimally invasive methods. CAS is also known as computer aided surgery, computer assisted intervention, image guided surgery, and surgical navigation.
An important component of CAS is the development and construction of an accurate model of the patient with an exceptionally accurate means to determine instrument positioning using the acquired or determined patient model. Medical imaging methods which produce such models include CT scans, MRI, x-rays, and ultrasound to name a few. It is a goal of such imaging methods to produce a 3D data set which ultimately yields a virtual image of the patient's soft and hard tissues. This virtual patient model when employed with a patient in position registered to the model, can be referenced during the actual surgery upon the patient to help the surgeon guide instruments, take tissue samples, and perform other surgical procedures. Matching a patient virtual model to the actual patient is often referred to as patient registration.
The actual patient intervention in CAS occurs as surgical navigation. Here, a surgeon and a computer controlled surgical robot, or the surgeon, must correlate their procedural actions. In general, the surgical robot is preprogrammed to carry out certain tasks during preoperative procedures. Robot surgery can conventionally be divided to three types, namely, supervisory-control, telesurgical, and shared-control. In the former, the robot solely performs the tasks via pre-programmed actions.
In telesurgical type systems, a surgeon remotely operates controls to manipulate robotic arms, this type is also called remote surgery. The latter is similar to remote surgery, however, the robot can be programmed to steady the instruments during manipulation by the surgeon. As can be imagined, the desired mode of surgery will vary from case to case depending on complexities and the particular case at hand.
Additional surgical procedures, using virtual models and patient registration for navigation, are performed by the surgeons themselves, frequently using their deft surgical skills. During such procedures the surgeon employs the virtual model and patient in a registered position to determine the exact position of a surgical instrument being controlled by the surgeon. Such a procedure includes for instance, tissue sampling in the lungs, where it is very important to sample tissue from particular positions in the lung. Using surgical navigation systems, the surgeon can ascertain exact positioning during the tissue sampling and obtain samples from deep within the lung.
For nearly all types discussed above, during the operation, it is necessary to correctly navigate the surgical instruments being employed during a procedure. Common surgical instruments include, needles, guidewires, stents, filters, occluders, retrieval devices, leads, catheters, cytology brushes, biopsy forceps, as well as others. Navigation and monitoring of the exact positioning in the patient's body of such surgical instruments is accomplished by the employment of tracking instrument reference markers, as well as non-tissue internal and external reference markers or sensors. Often the instrument reference marker is tracked in real time and relayed to a visual output, such as a computer screen, showing the location of the instrument within a virtual patient image. In the case where tracking is accomplished via electromagnetic systems, the markers are coils to which must be communicated an induced voltage to broadcast their position. Using multiple detectors in multiple positions, the coil position can be monitored extremely accurately and virtually positioned to coordinate positions within the virtual image. Thus, an extremely accurate image guided surgical navigation is provided.
One typical problem encountered with image guided surgical navigation however, is the physical mounting of the electromagnetic (EM) markers (herein the terms ‘EM marker’, ‘marker’, ‘EM sensor’, and ‘sensor’ may be used interchangeably and refer to any such marker or sensors deemed suitable for the intended purpose of image guided surgical navigation) to the surgical instruments themselves. As one could imagine, the precision and accuracy needed during surgical procedures requires sensors which are extremely small and extremely sensitive which renders them extremely fragile.
Conventionally, it is required to engage the marker or sensor to the tip or distal end of a lead wire providing current to the marker, as well as the surgical instrument. Additionally the sensor must be maintained in a dry condition and accurately positioned on the surgical instrument being employed, which only adds to the difficulty of such a mounting.
Current conventional mounting techniques for engaging small EM sensors to lead and power wires, include soldering, crimping, and adhesives. However, in reference to the problems discussed above, and with further development of even more sensitive and fragile sensors, the conventional mounting methods simply fall short. Using conventional methods of mounting, the electrical connection between the sensing element and electrical lead wire frequently disengages or becomes damaged. Further, using heat of soldering or welding, or crimping, to engage the small and fragile EM sensor to a lead wire is frequently damaging to both the sensor and the connection yielded.
If the sensor or electrical connection is advertently damaged, at this point during manufacture, it can cause the electrical connection to be disturbed or destroyed. If this happens and is found during quality control, the device is determined useless and the valuable part, with many man hours invested to form it, is wasted. This drives up costs for the manufacturer as well as medical customers. Should the poor or failing connection get past quality control and fail during surgery, the tracking and therefor navigation will be incorrect and is unacceptable. Worse, failure or mis-information as to location can endanger the patient.
As such, there is a continuing unmet need for an improved EM sensor mounting system for medical instruments employing fragile small sensors engaged to lead wires communicating with a surgical instrument, as needed for surgical navigation. The device and method should be employable for all types of sensors and marker used in the art of surgical navigation, but especially for EM type devices which depend upon a radiated pattern of transmission for accuracy. Such a device and method should advantageously provide improved mounting means for a plurality of medical instruments without damaging the sensor, marker, or lead wires while concurrently providing an insulated cover to protect from abrasion and moisture.